[Zackk1993]

Hello everyone! I'm new here and I don't know too much about 2 strokes, other than how to ride and simple things. Just recently my 2004 Blaster started to backfire whenever I'm at high RPM's. Before, it wouldn't backfire and just started after I had it going full speed. I checked the exhaust and there doesn't seem to be a leak. It also seems to be backfiring towards the motor/carburetor. I'm not sure if it could be my power reeds or something. If anyone knows what could be causing this I would greatly appreciate it!
Thanks,
Zack

 

[mgty3whlr]

Zack.... A couple of thing could be causing the issue.
Bad spark plug...bad reeds...
If you pull the air filter off..start it up and have a friend rev it up and see if there js fuel or blowby coming out of the intake...if so then you have bad reeds.
Most likely, it a bad spark plug...also, did you run the quad thru water ? cause you might have a spark plug wire or wiring issue due to moisture.. don't think it may be an ignition stator issue but we need more info on when it occurs and if you were riding it thru water puddles.

 

[Zackk1993]

Thanks for your feedback. And no I wasn't in any water/mud. It never backfired until I carried a passenger with me for about a quarter mile, than I went for a ride by myself and topped it out. I shut it off and whenever I started it again it backfired and at high RPM's is the only time it does.

 

[mgty3whlr]

Try changing the spark plug. When you pull it out also, what tell us what color the plug looks like to get an idea of the jetting.

 

[Zackk1993]

The bottom of the plug had oil on it and really dirty. Also, the backfire is up by the spark plug, but on the right side of the motor a little below the spark plug. Is that just the spark plug than?

 

[Zackk1993]

It's backfiring right in between the first slot that are almost against each other

 

[mgty3whlr]

starting to wonder if you have a bad head gasket.
do you have a compression gauge or have access to one?

 

[2000CR250]

Yeah my guess is a bad head gasket